universal-datepicker/src/js/helpers/index.js

Pure 8kb Vanilla Javascript plug and play datepicker

export const getDaysInMonth = (month, year) => {
  return new Date(year, month + 1, 0).getDate();
};

export const getDayInWeek = (month, year) => {
  return new Date(year, month, 0).getDay();
};
export const dateInRange = (checkin, checkout, date) => {
  return date > checkin && date < checkout;
};

export const differenceInDays = (date1, date2) => {
  if (!!date1 && !!date2) {
    const oneDay = 24 * 60 * 60 * 1000; // One day = hours*minutes*seconds*milliseconds
    return Math.round(Math.abs((date1 - date2) / oneDay));
  }
  return 0;
};

export const isBefore = ({ year, month, day }, date2) => {
  const date1 = new Date(year, month, day);
  date2.setHours(0, 0, 0, 0);

  return date1 < date2;
};

export const addDays = (date, days) => {
  const newDate = new Date(date);
  const updateDate = newDate.setDate(newDate.getDate() + days);
  return new Date(updateDate);
};

export const formatToday = (today) => {
  if (today instanceof Date) return today;

  if (typeof today === "string") {
    const stringReg = /^\d{4}[/]\d{2}[/]\d{2}$/;
    const isValidString = stringReg.matches(today);
    if (isValidString) return new Date(today);
    else return new Date();
  }

  if (typeof today === "object") {
    if (today.year && today.month && today.day) {
      return new Date(year, month, day);
    }
  }

  return new Date();
};

export const str_pad = (n) => {
  return String("00" + n).slice(-2);
};